Metabolic Impact of Prospective Controlled Mediterranean Type Diets on Prostate Cancer

Inclusion Criteria:

* Males ≥18 years old
* High suspicion of prostate cancer (PCa) per urologist's clinical evaluation
* BMI \>18.5
* No prior PCa diagnosis or hormonal therapy (-ies)
* Ability to read, write, speak, and understand English
* Ability to provide informed consent
* Candidate for and elects active surveillance (AS) if diagnostic biopsy is positive
* Willingness to consume provided dietary interventions
* Adequate organ and marrow function: White blood cell count (WBC) ≥2,500/mcL, Absolute neutrophil count (ANC) ≥1,500/mcL, Platelets ≥100,000/mcL, Hemoglobin ≥9 g/dL (transfusions permitted), Total bilirubin ≤1.5 x the institutional upper limit of normal (ULN) (for subjects with Gilbert's disease ≤3.0 mg/dL), Aspartate aminotransferase (AST)/Alanine aminotransferase (ALT) ≤2.5 x institutional ULN, Creatinine clearance ≥51 ml/min as defined by Cockcroft-Gault equation

Exclusion Criteria:

* Currently consuming a Mediterranean, lower carbohydrate, ketogenic, vegan, vegetarian, high fiber diet (14g fiber \> per 1,000 Calories) and/or any supplements (including herbal), vitamins, minerals, that would interfere with diets being tested in the study as determined by dietitian and/or investigators.
* Previous intolerability to fiber-rich diets
* Colitis, Irritable Bowel Syndrome, or other gastrointestinal condition per clinician discretion
* Unwilling to undergo transperineal PCa biopsies
* Food allergies or other major dietary restrictions
* Receiving active medical treatment for Type I or Type II diabetes mellitus
* Prior antibiotic usage (i.e. within last 30 days) at time of consent
* Recent weight loss (both intentional and unintentional) as defined by 5%+ body weight in the last 30 days
* Undergone any type of weight loss surgery
* Any medical contraindications as determined by investigators
* High risk as defined by PSA≥20 and/or PI-RADS 5 lesion as per clinician evaluation
* History of diabetic ketoacidosis
* Gout
* Patients that are immunosuppressed (transplant history, on immunosuppression, etc.) as per clinician discretion
* Recent (within last 30 days) device implant/joint requiring antibiotics as per clinician determination
* Prior history of prostate biopsy infection
* Uncontrolled hypertension as defined by blood pressure greater than 140/80 (with or without medication)
* Gallbladder removed or plan to remove per clinician evaluation
* Other malignancies actively receiving systemic treatment as per clinician evaluation